This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Our objective is to continue characterizing the two existing HD monkeys, currently nine months old, and the new generation of HD monkeys. Thus a cohort of HD monkey founders will be established for further characterization as proposed in this study. This application proposes to continue monitoring disease development among the cohort of HD monkeys and monitoring the development of symptoms by non-invasive imaging and cognitive behavioral tests. The primary goals of this application are to perform in-depth characterization on HD monkeys and establish a cohort of HD monkeys with known genotypes and phenotypes. Thus we will evaluate if the HD monkey model is a better model to recapitulate HD in humans than a rodent model.